1. Technical Field
The present invention relates to electro-optical display devices and processes for manufacturing the same.
2. Related Art
It is generally known that when an electric field is applied to a dispersion of charged fine particles in a liquid, the fine particles are caused to migrate (are electrophoresed) in the dispersion by the Coulomb force. This phenomenon is referred to as electrophoresis.
Electrophoretic display devices utilize electrophoresis for displaying desired information (images). The electrophoretic display devices have memory characteristics, i.e., retain the image after voltage application is terminated. They also possess a wide viewing angle range and can display a high-contrast image with low power consumption.
Further, the electrophoretic display devices are non-emissive and thus do not cause severe eye fatigue as experienced with emissive display devices such as cathode ray tube displays. JP-A-2008-107484 and JP-A-2004-04773 disclose electrophoretic display devices having a partitioned structure in which a pair of substrates sandwich a partition wall that defines a plurality of spaces (hereinafter, also referred to as cells), and a dispersion of charged fine particles is enclosed within the cells.
The partitioned electrophoretic display device is obtained by supplying a dispersion into cells that are defined by a partition wall on an element substrate having a pixel electrode, and bonding a counter substrate having a counter electrode onto the surface opposite the element substrate. An adhesive is often used in the bonding of the substrates. However, the use of an adhesive involves posttreatment in order to, for example, remove the adhesive that has leaked on the outer surface.
Further, the adhesive can contaminate the dispersion, thereby preventing the device from achieving the desired electrophoretic performance. The production is otherwise such that the dispersion is supplied into the partitioned cells and is enclosed within the cells by a sealing layer, and thereafter the substrates are bonded to the appropriate surfaces with an adhesive. In such a case, the sealing layer is dissolved by the heat that is applied for the bonding, and the dissolution permits the dispersion to penetrate into the sealing layer, resulting in a degraded sealing performance.